EP3546365A1 - Detection of icing conditions for an aircraft by analysis of electrical power consumption - Google Patents

Abstract

The present invention relates to a method and system for detecting icing conditions for an aircraft, said aircraft comprising probes (5) installed on its skin as well as a computer (7) configured to acquire measurements of electrical intensities traversing the aircraft. sensors to manage their power consumption, said computer (7) being further configured to compare the electrical currents flowing through at least two probes (5) and to derive icing conditions from said comparison.

Description

TECHNICAL AREA

The present invention generally relates to the estimation of the meteorological conditions in which an aircraft is located and more particularly to the detection of icing conditions.

STATE OF THE PRIOR ART

The occurrence of icing conditions in flight may affect aircraft performance. Thus, when the aircraft are authorized to fly in icing conditions, they are equipped with protection systems, integrated into the elements to be protected (wing, engine air intakes, pitot probes, etc.). Protection systems are particularly in the form of heating systems preventing the formation or accumulation of ice.

The activation of at least some of these protection systems is generally based on the pilot's judgment after identifying the presence of icing conditions. Mechanical and / or optical sensing systems are generally used to assist the pilot in his judgment. It should be noted that some elements such as Pitot probes are continuously protected by heating systems and therefore, no pilot action is required to protect them from icing conditions. On the other hand, other elements such as airfoils and engine air intakes require for their protection a punctual pilot action following detection of icing conditions by the detection system.

Thus, it is common to equip an aircraft with sensors dedicated to the detection of icing conditions mounted on the skin of the aircraft and to exploit the measurements obtained to diagnose the presence of ice. An assessment of the measures by the pilot remains necessary taking into account the phase of flight, the criticality of the functions performed by the elements affected by frost and associated safety margins to prevent inadvertent activation of protection systems.

These specific detection sensors are installed on the skin of the fuselage or a surface of the aircraft, which, on the one hand, requires piercing the fuselage or the surface in question, to provide mechanical reinforcements near the hole, Deploy electrical wiring and install additional acquisition systems in electrical cabinets, increasing weight and cost. In addition, the specific sensors often protrude from the skin of the fuselage and therefore generate a drag that can affect the performance of the aircraft.

The current detection specific sensors fulfill their function of a global detection of icing conditions, but are not adapted to provide a more accurate diagnosis. Indeed, these specific sensors are not suitable for discerning the formation of large drops of water or ice crystals.

An object of the present invention is to provide a system for detecting icing conditions for an aircraft, which overcomes at least some of the above disadvantages, in particular which does not require additional drilling and cabling operations. increases neither the weight of the aircraft nor its aerodynamic drag, and allows both to apprehend a wide range of icing conditions and to provide a more accurate diagnosis than in the prior art.

STATEMENT OF THE INVENTION

The present invention relates to a system for detecting icing conditions for an aircraft, said aircraft comprising probes installed on its skin and a computer configured to acquire measurements of electrical intensities traveling through the probes in order to manage their power consumption, the wherein the computer is further configured to compare electrical intensities traversing at least two probes and to derive icing conditions from said comparison.

Thus, the comparison of the electrical current intensities already available probes can detect the presence of clouds, icing conditions and the concentration of water clouds. It is no longer necessary to install detectors frost-specific, reducing weight, costs, maintenance and power consumption.

Advantageously, the computer is configured to calculate the ratio of currents between first and second current currents respectively traversing first and second probes installed on different locations of the aircraft, said ratio being indicative of the icing conditions.

Thus, a simple calculation of the ratio of currents already measured makes it possible to have, surprisingly, a very reliable indication of the icing conditions.

Advantageously, the computer is configured to determine a parameter indicative of the icing conditions by dividing said current ratio by the ratio between first and second water capture coefficients relative respectively to said first and second probes as well as by an off-cloud constant.

The icing condition parameter is used to indicate the presence and type of icing conditions by discriminating between liquid and solid particles.

Advantageously, the water capture coefficients are predetermined by an aerodynamic code according to the flight conditions, the location of the probes and the atmospheric conditions, the values of said capture coefficients being recorded in charts which are stored in a unit. storage.

Advantageously, the cloudless constant is predetermined by measuring the ratio of currents relative to said first and second probes under dry air atmospheric conditions.

According to one embodiment of the present invention, the computer is further configured to derive the icing conditions using previously recorded training data. This broadens the detection spectrum and refines the interpretation of icing conditions.

Advantageously, the computer is configured to monitor over time the evolution of the parameter indicative of icing conditions during the various flights of the aircraft. This makes it possible to monitor the evolution of icing conditions and cloud water concentration.

Advantageously, the data of the icing conditions are indicated in real time on an interface to the cockpit of the aircraft.

This data thus helps the pilot in his judgment concerning the activation of the protection systems.

Advantageously, the computer is configured to compare in pairs the electrical intensities traversing a plurality of probes installed in different locations of the aircraft.

This allows to probe the cloud water concentration.

Advantageously, the data of the icing conditions determined by the computer are transmitted by the aircraft to a weather station on the ground.

Thus, the ground station can collect meteorological data from several sources at altitude.

The invention also relates to an aircraft comprising the system for detecting icing conditions according to any one of the preceding characteristics.

The invention also relates to a method for detecting icing conditions for an aircraft, said aircraft comprising probes installed on its skin and a computer configured to acquire measurements of electrical currents flowing through the probes in order to manage their power consumption, said method comprising a comparison of the electrical intensities traversing at least two probes and a deduction of the icing conditions from said comparison.

BRIEF DESCRIPTION OF THE DRAWINGS

• La Fig. 1 représente de manière schématique un aéronef comportant un système de détection de conditions givrantes, selon un mode de réalisation de l'invention;
• La Fig. 2 illustre de manière schématique un système de détection de conditions givrantes, selon un mode de réalisation préféré de l'invention ;
• La Fig. 3 illustre des courbes de coefficients de captation d'eau en fonction de la distance de la peau de l'aéronef et selon différentes conditions de vol de l'aéronef, selon l'invention ;
• La Fig. 4 est un graphique illustrant le paramètre indicatif des conditions givrantes, selon un mode de réalisation de l'invention ; et
• La Fig. 5 représente de manière schématique un procédé de détection de conditions givrantes selon un mode de réalisation de l'invention.

Other features and advantages of the invention will appear on reading a preferred embodiment of the invention, with reference to the attached figures among which:

• The Fig. 1 schematically represents an aircraft comprising a system for detecting icing conditions, according to one embodiment of the invention;
• The Fig. 2 schematically illustrates a system for detecting icing conditions, according to a preferred embodiment of the invention;
• The Fig. 3 illustrates curves of water capture coefficients as a function of the distance of the skin of the aircraft and according to different flight conditions of the aircraft, according to the invention;
• The Fig. 4 is a graph illustrating the indicative parameter icing conditions, according to one embodiment of the invention; and
• The Fig. 5 schematically represents a method for detecting icing conditions according to one embodiment of the invention.

DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS

The concept underlying the invention is to use current intensity measurements already available, without development and installation of specific external sensors and therefore without implantation of devices on the skin of the aircraft to detect the presence of conditions. icing. By specific sensors is meant here sensors whose measurements are intended exclusively for the detection of the presence of ice (for example an ice crystal detector).

The Fig. 1 schematically represents an aircraft comprising a system 1 for detecting icing conditions, according to one embodiment of the invention.

In general, an aircraft 3 comprises different types of probes 5 to monitor the flight conditions. Indeed, pitot-type fluid velocity probes, incidence angle probes, temperature probes, pressure probes, and so forth. are generally installed on the skin of the aircraft 3. In addition, heating elements and more particularly, electrical circuits 51 of heating are integrated in these probes to protect them from icing conditions. An electrical generation system (not shown) of the aircraft 3 permanently provides an electrical voltage to the various electrical circuits 51 of heaters integrated in the different probes 5. In addition, an aircraft monitoring system comprising a computer 7 , is configured to acquire measurements of electrical intensities going through the different probes 5 (more precisely the heating circuits 51) in order to manage their electrical consumption and to verify the proper functioning of their electric heating circuits 51. The electrical intensity passing through a probe 5 depends on the physical characteristics of the probe as well as flight conditions and atmospheric conditions.

According to the invention, the computer 7 is further configured to compare the electrical currents simultaneously traveling at least two probes 5 installed on the aircraft. From this comparison, the computer 7 is configured to deduce the icing conditions.

The power consumption of the probes 5 depends on the heat dissipation in the atmosphere from the electrical circuits 51 of the heaters. This heat dissipation is correlated with atmospheric conditions (temperature, pressure, water concentration in clouds, etc.) and the flow of air around the probe. Thus the heat dissipation is further related to the location of the probes 5 on the fuselage. By analyzing the disparities between the electrical intensities of the different probes 5, the computer 7 is configured to deduce the icing conditions.

The Fig. 2 schematically illustrates a system for detecting icing conditions, according to a preferred embodiment of the invention.

According to this embodiment, the computer 7 is configured to acquire first and second current currents i _A and i _B respectively browsing first 5A and second 5B probes installed on different locations of the aircraft. In addition, the computer 7 is configured to calculate the ratio of currents between the first i _A and second i _B current intensities.

It has been found that in a cloudless sky (ie without icing), the ratio of currents relative to two given probes is always equal to a constant C (called in the following constant C out of cloud) for given flight conditions (altitude , temperature, incidence, Mach number): $$\frac{i_{\mathrm{AT}}}{i_B}=\mathrm{VS}$$

This already gives a first indication in the sense that if this ratio is not equal to the constant C out of cloud, the computer 7 can directly deduce that the aircraft is in a cloudy zone.

où C est la constante hors nuage pour les conditions de vol données, k un paramètre indicatif des conditions givrantes, et le ratio $\frac{{\beta }_A}{{\beta }_B}$

est le rapport entre des premier et deuxième coefficients de captation d'eau relatifs respectivement aux première 5A et deuxième 5B sondes.More generally, in any atmospheric environment and taking into account that the probes can undergo different local air flows and different local water concentrations, the ratio of the current intensities relative to the first 5A and the second 5B probes can be expressed. as follows : $$\frac{i_{\mathrm{AT}}}{i_B}=\frac{{\beta }_{\mathrm{AT}}}{{\beta }_B}\cdot k\cdot \mathrm{VS}$$

where C is the non-cloud constant for the given flight conditions, k is a parameter indicative of icing conditions, and the ratio $\frac{{\beta }_{\mathrm{AT}}}{{\beta }_B}$

is the ratio between first and second water capture coefficients relating respectively to the first 5A and second 5B probes.

The water uptake coefficients β _A and β _B are predetermined by an aerodynamic code depending on the flight conditions, the location of the probes 5A, 5B and the type of icing atmospheric conditions (liquid water or crystals). The calculation of these coefficients is already done as part of the certification of the aircraft and their values are recorded in charts previously constructed following the aerodynamic calculations. These charts are stored in a storage unit 9 associated with the computer 7.

The Fig. 3 illustrates by way of example curves of water capture coefficients as a function of the distance of the skin of the aircraft and according to different flight conditions of the aircraft, according to the invention.

The curves illustrated are made for water droplets having diameters of a few microns and each curve represents a given speed or flight condition of the aircraft. It should be noted that the general shape of a curve of coefficient β is increasing while moving away from the skin of the aircraft to a certain value which depends on the speed of the aircraft and then decreasing by tending asymptotically towards the value "1". The curve of a coefficient β gives an accurate indication of the location of a probe and especially its distance from the skin of the aircraft.

relatif aux première 5A et deuxième 5B sondes est par conséquent facilement calculé par le calculateur 7 à partir des valeurs consignées dans les abaques enregistrés dans l'unité de stockage 9.The coefficient β can then advantageously be considered as an installation parameter of a probe. Moreover, since the location of each probe 5 on the aircraft 3 is known, the ratio $\frac{{\beta }_{\mathrm{AT}}}{{\beta }_B}$

for the first 5A and second 5B probes is therefore easily calculated by the computer 7 from the values recorded in the charts recorded in the storage unit 9.

est facilement calculé par ce dernier.In addition, the first and second current intensities i _A and i _B respectively traversing the first 5A and second 5B probes are already acquired by the calculator 7 and their ratio. $\frac{i_{\mathrm{AT}}}{i_B}$

is easily calculated by the latter.

par le rapport $\frac{{\beta }_A}{{\beta }_B}$

entre les premier et deuxième coefficients de captation d'eau relatifs respectivement aux première 5A et deuxième 5B sondes ainsi que par la constante C hors nuage.Likewise, the out-of-cloud constant C is predetermined by a simple calculation of the current ratio relative to the first 5A and second 5B probes under dry air atmospheric conditions. Advantageously, the value of the constant C out of cloud relative to the corresponding probes is also prerecorded in the storage unit 9. Thus, the parameter k indicative of the icing conditions is determined by the calculator 7 by dividing the ratio of currents $\frac{i_{\mathrm{AT}}}{i_B}$

by the report $\frac{{\beta }_{\mathrm{AT}}}{{\beta }_B}$

between the first and second water capture coefficients relating respectively to the first 5A and second 5B probes as well as the constant C out of cloud.

The Fig. 4 is a graph illustrating the indicative parameter icing conditions, according to one embodiment of the invention.

de courants relatif aux intensités de courant parcourant les première 5A et deuxième 5B sondes. Le deuxième paramètre (courbe C2) représente le rapport $\frac{{\beta }_A}{{\beta }_B}$

des coefficients de captation d'eau relatif aux emplacements des première 5A et deuxième 5B sondes. Finalement, le troisième paramètre (courbe C3) représente le paramètre k indicatif des conditions givrantes déterminé en fonction du ratio $\frac{i_A}{i_B}$

de courants, du rapport $\frac{{\beta }_A}{{\beta }_B}$

de captation d'eau et de la constante C hors nuage. On notera que les sauts S1, S2, S3 simultanés illustrés respectivement sur les courbes C1, C2, C3 des trois paramètres indiquent la présence de conditions givrantes durant le temps de vol relatif à ces sauts S1, S2, S3. Un post-traitement supplémentaire peut être réalisé par le calculateur en comparant plus finement les valeurs du paramètre k avec les abaques enregistrés dans l'unité de stockage 9.More specifically, this graph illustrates three parameters as a function of flight time. The first parameter (curve C1) represents the ratio $\frac{i_{\mathrm{AT}}}{i_B}$

currents relative to the currents current flowing through the first 5A and second 5B probes. The second parameter (curve C2) represents the ratio $\frac{{\beta }_{\mathrm{AT}}}{{\beta }_B}$

water capture coefficients relative to the locations of the first 5A and second 5B probes. Finally, the third parameter (curve C3) represents the parameter k indicative of the icing conditions determined according to the ratio $\frac{i_{\mathrm{AT}}}{i_B}$

current, report $\frac{{\beta }_{\mathrm{AT}}}{{\beta }_B}$

of water uptake and the constant C out of the cloud. It will be noted that the simultaneous jumps S1, S2, S3 illustrated respectively on the curves C1, C2, C3 of the three parameters indicate the presence of icing conditions during the flight time relative to these jumps S1, S2, S3. Additional post-processing can be performed by the computer by comparing more precisely the values of the parameter k with the charts recorded in the storage unit 9.

Advantageously, in order to interpret the parameter k of the icing conditions more precisely, a test aircraft (not illustrated) equipped with the detection system 1 according to the invention is used, as well as a specific system comprising test sensors. dedicated to the direct and accurate detection of cloud water concentration, frost, and water content (crystals and supercooled water). Indeed, during test flights of the test aircraft, the values of the parameter k are determined by the detection system 1 according to the invention at the same time as the acquisition of precise data by the specific system dedicated to direct detection. These precise data are analyzed and correlated with the values of the parameter k to form supervised learning data.

Thus, during an operational flight of an aircraft 3, generally of the same type as that used for test flights, except that this time it does not include specific test sensors, the computer 7 determines the values of the parameter k and compares them with the prerecorded supervised learning data in the storage unit 9 in order to apprehend a wide range of icing conditions by interpreting the values of the parameter k more precisely.

In addition, the computer 7 is configured to transmit in real time the data of the icing conditions to an interface 11 of the cockpit of the aircraft 3 (see FIG. Figs. 1 and 2 ). Thus, this data can be displayed on a screen 111 of the cockpit and possibly generate an alarm. The pilot will then be able to activate the ice protection systems. Alternatively, the icing condition may automatically trigger ice protection systems.

Advantageously, the computer 7 is configured to monitor over time the evolution of the indicative parameter icing conditions during the various flights of the aircraft 3 to monitor the evolution of the water concentration in the clouds.

Moreover, the data of the icing conditions determined by the computer 7 can be transmitted by the aircraft 3 to a weather station on the ground. The ground station can thus analyze in more detail these data and is advantageously in possession of meteorological data from several sources at altitude.

The Fig. 5 schematically represents a method for detecting icing conditions according to one embodiment of the invention.

In step E1, measurements of electrical intensities traversing 5A-5C probes installed on the aircraft are collected for example, at regular intervals of the flight.

In steps E2-E4, electric currents i _A and i _B browsing at least two probes 5A, 5B installed in different parts of the aircraft are compared and icing conditions are deduced from this comparison. In the case where the measurements of electrical intensities are collected from a plurality of probes, the latter are grouped in pairs by choosing in each pair of two probes installed on different locations of the aircraft. For simplicity, reference is made below to only two current intensities collected from two probes (first 5A and second 5B probes).

entre des première et deuxième intensités i_A et i_B de courant parcourant respectivement les première 5A et deuxième sondes 5B est calculé.More particularly, in step E2, the current ratio $\frac{i_{\mathrm{AT}}}{i_B}$

between first and second currents i _A and i _B current flowing respectively the first 5A and second probes 5B is calculated.

entre des premier et deuxième coefficients de captation d'eau est calculé.In step E3, the values of the water capture coefficients relative to the first 5A and second 5B probes are sought from the pre-established charts. The acquired values are those that correspond to the locations of the first and second probes as well as to the current flight conditions. Then the report $\frac{{\beta }_{\mathrm{AT}}}{{\beta }_B}$

between first and second water capture coefficients is calculated.

de courants, du rapport $\frac{{\beta }_A}{{\beta }_B}$

entre les premier et deuxième coefficients de captation d'eau et de la constante C hors nuage enregistrée préalablement dans l'unité de stockage.In step E4, the indicative parameter k of the icing conditions is calculated according to the ratio $\frac{i_{\mathrm{AT}}}{i_B}$

current, report $\frac{{\beta }_{\mathrm{AT}}}{{\beta }_B}$

between the first and second coefficients of water uptake and the constant C out of cloud previously recorded in the storage unit.

In step E5, the determination of the icing conditions is possibly carried out more accurately taking into account the supervised learning data previously recorded.

In step E6, the icing conditions are displayed on a screen 111 of the cockpit and possibly an alarm 112 is generated when frost is detected. The pilot will have then the possibility of activating the frost protection systems. Alternatively, the icing condition may automatically trigger ice protection systems.

Claims (9)

Icing detection system for an aircraft comprising probes (5) installed on the skin of the aircraft and a computer (7) configured to acquire measurements of electrical intensities traveling through the probes in order to manage their power consumption , characterized in that the computer (7) is further configured for: calculating the ratio of currents between first and second current currents respectively traversing the first and second probes (5A, 5B) installed on different locations of the aircraft, said ratio being indicative of the icing conditions; and to determine a parameter indicative of the icing conditions by dividing said current ratio by the ratio between first and second water capture coefficients respectively relative to said first and second probes (5A, 5B) as well as by a constant outside the cloud. System according to claim 1, characterized in that the water capture coefficients are predetermined by an aerodynamic code according to the flight conditions, the location of the probes and the atmospheric conditions, the values of said capture coefficients are recorded in charts that are stored in a storage unit (9). System according to claim 1, characterized in that the cloudless constant is predetermined by a measurement of the current ratio relative to said first and second probes (5A, 5B) under dry air atmospheric conditions. System according to any one of the preceding claims, characterized in that the computer is further configured to derive the icing conditions using previously stored training data. System according to any one of the preceding claims, characterized in that the data of the icing conditions are indicated in real time on an interface to the cockpit of the aircraft. System according to any one of the preceding claims, characterized in that the computer (7) is configured to compare in pairs the electrical intensities traversing a plurality of probes installed in different locations of the aircraft. System according to any one of the preceding claims, characterized in that the data of the icing conditions determined by the computer (7) are transmitted by the aircraft to a weather station on the ground. Aircraft comprising the icing condition detection system according to any one of the preceding claims. A method for detecting icing conditions for an aircraft, said aircraft comprising probes installed on its skin, characterized in that said method comprises the following steps: acquire measurements of electrical intensities going through the probes, calculating the ratio of currents between first and second current currents respectively traversing the first and second probes (5A, 5B) installed on different locations of the aircraft, said ratio being indicative of the icing conditions; and determining a parameter indicative of the icing conditions by dividing said ratio of currents by the ratio between first and second water capture coefficients relative respectively to said first and second probes (5A, 5B) as well as by a constant outside the cloud.

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